Non-Forested Wetlands

Diseases and insect pests are currently not responsible for much mortality in mature red pine stands, but they may become more damaging under warmer conditions. Longer growing seasons and milder winters might allow populations of native forest pests to build more rapidly, and many pests have been shown to be more damaging when interacting with trees that are already stressed due to droughts or other impacts. New agents such as annosum root rot or western bark beetles may also enter northern Minnesota in the future.

Multiple forest impact models tend to agree that this species is more likely to increase or remain constant in suitable habitat and biomass under a mild climate scenario by the end of the century. Under a more extreme climate scenario, results are mixed. Suitable habitat for red pine may shift from north-central Minnesota to northeast Minnesota by the end of the century. Particular areas may become more or less suitable, but changes are projected to be moderate across northern Minnesota.

Natural regeneration is very rare in managed red pine systems due to shoot blight and deer herbivory, so maintaining red pine in these stands depends on planting seedlings following harvest. Seasonal shifts in precipitation patterns may impair the survival of planted seedlings, particularly if the trend is for wetter springs and drier summers.

Red Pine is adapted to withstand low-severity wildfire and other disturbances. Managed Red Pine stands occur on a range of soil types in northern Minnesota, from dry to mesic. Therefore there will likely continue to be suitable planting locations for these forests in the future. Wildfire is typically excluded from Managed Red Pine stands and fire is not used as a management or regeneration tool, so it is unclear whether more frequent wildfire would benefit managed red pine forests.

The potential exists for negative interactions between stressors in these forests, such as earthworms, insect pests, drought, and diseases. Each of these stressors is generally expected to be more damaging under climate change, but it's hard to predict how they may act in combination.

Managed Aspen forests that contain a diversity of species, age classes, and structures may be more resilient to changing conditions than forests with few species and uniform age classes and structure. Diversity in all of these features can give a forest more possible pathways to respond to changing or unexpected conditions.

Insect pests such as forest tent caterpillar and gypsy moth, along with diseases like hypoxylon canker, may become damaging under a warmer climate. Longer growing seasons and milder winters might allow populations of native forest pests such as forest tent caterpillar to build more rapidly, and many pests have been shown to be more damaging when interacting with trees that are already stressed due to droughts or other impacts. The possibility also exists for new pests such as gypsy moth and Asian longhorn beetle to arrive in northern Minnesota.

Multiple forest impact models tend to agree that this species is more likely to decrease in suitable habitat and biomass across a range of climate scenarios by the end of the century. Quaking aspen is a boreal species near its southern range limit in Minnesota. Model results for bigtooth aspen are mixed.

Research from the western US suggests that aspen might be vulnerable to prolonged droughts, and a range of climate scenarios suggest that northern Minnesota may experience more drought stress under climate change. Earthworm activity in aspen sites may also make these forests more susceptible to droughts.

Aspen is adapted to withstand wildfire, blowdowns, and pest outbreaks. Aspen can reproduce vegetatively following natural distrubance or management. Managed aspen stands also can occur on a range of soil types, from dry to mesic. This lends them a competitive advantage and the possibility to opportunistically occupy disturbed areas. Increased wildfire activity could help maintain aspen across the assessment
area. However, with frequent disturbance from increased wildfire, drought, or more intensive management, aspen could become a less successful competitor in the future.